Citations 765

Impact of MYD88L265P mutation Status on Histological Transformation of Waldenstrom Macroglobulinemia

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 2884-2884

10.1182/blood-2018-99-120046

Abstract Background: Limited data exist regarding histological transformation in patients with Waldenström macroglobulinemia (WM). In this study, we present the disease characteristics, outcomes and risk factors for histological transformation in WM. Methods: Patients with WM seen at Mayo Clinic, Rochester, MN between January 1996 and December 2017 were included. Patients with aggressive non-Hodgkin lymphoma in the setting of WM were considered to have transformation. Univariate analysis for comparing baseline characteristics of transformed versus non-transformed WM was performed using Wilcoxon, Fisher's exact and Chi square tests, as appropriate. Multivariate analysis was performed using logistic regression analysis. Cox proportional hazard method was used to assess the impact on time-to-transformation. All time-to-event analyses were calculated by the Kaplan-Meier method. Results: Of 1014 patients with WM, 42 patients (4.1%) developed histological transformation. The median follow-up for the entire cohort was 9.5 years (95% CI: 8.8-10.5 years). The cumulative probability of transformation was 2.3% at 5 years, 5.3% at 10 years and 8.5% at 15 years from diagnosis of WM, respectively. There was no difference in the 5-year cumulative probability of transformation in patients with WM diagnosed between 1996-2000 (2.1%), 2001-2005 (2.9%), 2006-2010 (2.7%) and 2011-2015 (3.8%), p=0.61.The disease characteristics, laboratory parameters and histology at transformation are outlined in Table 1. In patients with DLBCL histology (n=39), Revised-International Prognostic Index was calculable in 28 patients, with 50% (n=14), 46% (n=13) and 4% (n=1) of DLBCL belonging to poor, good and very good risk groups, respectively. For DLBCL histology, 18 patients were classifiable using Hans algorithm into germinal center B-cell (GCB) type (n=3, 17%) and non-GCB type histology (n=15, 83%). The median lines of therapy received prior to transformation for the entire cohort was 2 (range 0-9), with 5 (11%) patients not having received any therapy for WM before transformation. Number of lines of alkylator-based therapy used prior to transformation [median 1 line (range 0-4)] was comparable to that used in patients in whom WM did not occur [median 1, (range 0-6); p=0.78]. The median time-to-transformation from diagnosis of WM was 4.8 years (95% CI: 2.6- 6.8 years). Overall survival (OS) from transformed disease was 3.2 years (95% CI 1.1-3.9 years). The 10-year OS of patients with WM who transformed was lower (46%) compared to patients without transformation (60%) with a trend towards statistical significance (p=0.08), Figure 1. The MYD88L265P mutation status was available in 333 patients in the entire cohort (22/42 pts in the transformed cohort and 311/972 in the non-transformed cohort. Of the 22 patients in the transformed WM cohort, 13 (59%) exhibited MYD88WT genotype and 9 (41%) exhibited MYD88L265P genotype. The risk of transformation was higher in patients with MYD88WT status [Odds ratio 6.3 (95% CI: 2.6-15.5); p<0.0001]. Additionally, serum lactate dehydrogenase (LDH) was higher at diagnosis of WM in patients who transformed, Table 2. On multivariate analysis, MYD88WT status remained an independent predictor of disease transformation [p=0.003; odds ratio 10 (95% CI: 2.1-48)]. On univariate Cox proportional hazard analysis for identifying predictors of time-to-transformation, only MYD88WT mutational status was associated with shorter time-to-transformation with a 5-year transformation rate of 15.5 % for MYD88WT versus 2.6 % with MYDL265P mutated patients [risk ratio 6.2 (95% CI: 2.5-16.4); p<0.0001]. Treatment-related details in the transformed cases were available for 37 (90%) patients; R-CHOP was the most common (41%) frontline therapy for transformation; 33% patients underwent autologous stem cell transplantation for transformed disease during their disease course. Conclusion: Histological transformation is an uncommon event in WM but confers poorer survival. MYD88WT genotype is independently associated with histological transformation a shorter time-to- transformation in patients with WM. Disclosures Ansell: Trillium: Research Funding; Pfizer: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding; Takeda: Research Funding; Celldex: Research Funding; Regeneron: Research Funding; Merck & Co: Research Funding; Bristol-Myers Squibb: Research Funding. Gertz:Apellis: Consultancy; Alnylam: Honoraria; spectrum: Consultancy, Honoraria; janssen: Consultancy; annexon: Consultancy; Prothena: Honoraria; Abbvie: Consultancy; Amgen: Consultancy; celgene: Consultancy; Teva: Consultancy; Medscape: Consultancy; Ionis: Honoraria; Research to Practice: Consultancy; Physicians Education Resource: Consultancy. Dingli:Millennium Takeda: Research Funding; Millennium Takeda: Research Funding; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Lacy:Celgene: Research Funding. Kumar:Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kapoor:Takeda: Research Funding; Celgene: Research Funding.
Role of Systemic High-Dose Methotrexate and Combined Approaches in the Management of Vitreoretinal Diffuse Large B-Cell Lymphoma: A Single Center Experience 1990-2018

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 574-574

10.1182/blood-2018-99-113826

Abstract Introduction. Vitreoretinal lymphoma (VRL) is a rare ocular malignancy. Diagnosis and optimal treatment remain a challenge for clinicians. We present clinical characteristics and outcome of a cohort of 69 patients affected by vitreoretinal diffuse large B-cell (DLBCL) lymphoma treated at Mayo Clinic over a 28-year period. Methods. We accessed the Mayo Clinic Lymphoma Data Base to identify all patients > 18 years old with VRL diagnosed between 01/01/1990 and 01/31/2018. Only patients with DLBCL, confirmed at pathological review, were included. Clinical characteristics, therapies, response, relapse patterns and follow up status were collected and analyzed in the cohort and in the different subgroups: primary (PVRL, localized only in eye at diagnosis) vs concurrent (CVRL) vs secondary VRL (SVRL). Chi-squared test, Fisher's exact test and Wilcoxon's signed-rank test were used for analysis. Failure-free survival (FFS), overall survival (OS), central nervous system (CNS) and eye relapse-free survival were analyzed according to Kaplan Meier method. Differences between subgroups were compared with log-rank test. Since the group of SVRL can be affected by a survivorship selection bias, it was investigated separately for the outcome analysis. Results. A total of 69 patients with vitreoretinal DLBCL were included. At diagnosis, 33 (48%) were PVRL, 18 (26%) CVRL (eye plus CNS (N=17) or systemic (N=1) disease) and 18 (26%) had SVRL (9 primary CNS lymphomas, 9 systemic at diagnosis, among which 4 were primary testicular lymphomas). Unilateral intraocular involvement was observed in 16 (23%) cases. Clinical characteristics are reported in Table I. At diagnosis, patients received a systemic treatment in 35 (50%, including high-dose systemic MTX (HD-MTX, N 14, 20%), MTR (HD-MTX, Temozolomide and Rituximab) (N 7, 10%) and CHOP (Cyclophosphamide, Doxorubicin, Vincristine and Prednisone) with or without Rituximab (N 10, 15%)), combined systemic plus intraocular treatment in 15 (22%), local radiotherapy in 10 (14%) and intraocular therapy (intraocular injections of rituximab or MTX or steroids or a combination of these) in 9 (13%) cases. Systemic Rituximab, autologous stem cell transplantation (ASCT) and therapeutic vitrectomy/enucleation were performed in 36 (53%), 20 (29%) and 5 (7%) patients, respectively. The median number of treatments was 2 (range 0-10). Among PVRL and CVRL (N=51), median FFS, CNS relapse-free survival, eye relapse-free survival and OS were: 1.8 y, 4.9 y, 3.8 y and 4.1 y, respectively (Fig 1). Among PVRL they were: 2.6 y, not reached (NR), 5.2 y and 9.3 y, respectively. No CNS relapse occurred beyond 4 years in the PVRL subgroup. The median OS for patients diagnosed between 1990 and 1999, in contrast to 2000 and 2018 was 1.5 y vs 9.4 y respectively (p= 0.0002). OS was significantly higher in PVRL, as compared to CVRL (p= 0.04). Previous immunosuppression and poor performance status were predictive of worse outcome (p=0.04), while ASCT correlated with higher OS (p= 0.009). In PVRL, a combined systemic + intraocular therapy was associated with higher FFS (p=0.002) and CNS-relapse free survival (p= 0.003), but no difference in OS was observed. Among 18 SVRL, at a median follow-up of 1.1 y after vitreoretinal relapse, median FFS and OS were 0.3 y and 1.3 y, respectively. Systemic toxicities included 8 (11.6%) acute renal failures, 8 (11.6%) infections, and 3 (4.3%) hemorrhages. Intraocular toxicities included cataract in 11, vitreal detachment in 3 , ocular hypertension in 5, retinal vessel occlusion in 3 and keratitis in 2 cases. Of 69 patients, 39 (56.5%) died secondary to lymphoma (N=21, 53.8%), infectious toxicity (N=2, 5.2%), unrelated (N=3, 7.7%) or unknown (N=13, 33.3%) causes. Conclusions. VR DLBCL is a rare disease, which can occur as primary, concurrent with systemic, or in relapsed disease. OS over the decades has significantly improved. In PVRL, no late CNS relapses were observed, while late intraocular relapses can occur. A combined approach with intraocular + systemic HD-MTX based treatment at diagnosis was associated with a higher FFS and CNS-relapse free survival in PVRL and is recommended in bilateral involvement, even though no differences in OS were observed. Treatment consolidation with ASCT can be considered in cases with concurrent systemic disease. Further studies are needed to confirm these results and to better define the role of new drugs in treatment of this uncommon malignancy. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.
Depth of Response in Waldenstrom Macroglobulinemia

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 4141-4141

10.1182/blood-2018-99-111540

Abstract Introduction Recent advances in the understanding of the WM pathobiology led to the expansion of our therapeutic options in this disease. A number of targeted drugs are either available or under investigation and are poised to change the chemo-immunotherapy paradigm in the treatment of WM. Now more than ever, an individualized treatment approach for patients with WM is possible, where patient characteristics and preferences can be matched by different treatment goals and side effect profiles. While deep responses have been associated with longer disease-free survival in other hematologic malignancies, data on patients with WM are sparse. We report the impact of depth of response in disease-free and overall survival (OS) in WM. Methods WM patients consecutively seen at Mayo Clinic between 01/1998 and 12/2016 were reviewed for response to therapy and disease burden. The best response achieved after the treatment of interest (TOI) was classified using the IWWM-7 Response Criteria. The included TOI were: BR, DRC, BDR and high-dose chemotherapy followed by ASCT. All time-to-event analyses were performed from the TOI initiation date using the Kaplan-Meier method and the log-rank test. A landmark analysis from the date-of-best response was also performed for OS to prevent immortal-time bias. Univariate and multivariate analyses of progression-free survival (PFS) and time-to-next therapy (TTNT) were performed using the Cox regression method. Results A total of 181 patients had disease response assessed after the TOI. Baseline characteristics at time of diagnosis are summarized in table 1. The median follow up from TOI was 3.8 years (95% CI: 3-4), the majority of patients received TOI as salvage therapy [n=112 (63%); median 2nd line (rage 1-11)]. Best response rates with the corresponding 5-year PFS and TTNT are summarized in table 2. The median OS from TOI was longer in patients who achieved at least a PR [median 7.2 years (95% CI: 5-NR) vs 3.7 years (95% CI: 1.6-NR), p=0.01]. A trend towards a longer OS was also seen with deeper responses (PR or better) achieved with frontline therapy [median 5.8 years (95% CI: 5.8-NR) vs 3.4 years (95% CI: 1.6-NR), p=0.24]. Figure 1 shows the correlation between deeper responses with PFS and TTNT. Among patients achieving a PR or VGPR, those with a normal FLC ratio post TOI demonstrated a longer PFS and TTNT [PFS: median NR (95% CI: 3.4-NR) vs 4.9 years (95% CI: 2.8-8.7), p=0.01; TTNT: median NR (95% CI: 3.5-NR) vs 5.2 years (95% CI: 4.2-9.4), p=0.04], figure 2. In a multivariate analysis including normal FLC ratio, normal IgM level and minimal BM involvement (<5%) post TOI, normal FLC ratio remained an independent prognostic factor for longer PFS and TTNT. Similar trends were seen when considering treatment naïve and relapsed/refractory patients independently (data not shown). Discussion Our results not only suggest an association between depth of response with PFS and TTNT, but also with OS in patients with WM. A normal FLC ratio (not part of the IWWM-7 response criteria) seems to predict a longer disease-free interval in patients achieving a PR or VGPR. Disclosures Gertz: Ionis: Honoraria; Apellis: Consultancy; annexon: Consultancy; Prothena: Honoraria; janssen: Consultancy; Physicians Education Resource: Consultancy; Alnylam: Honoraria; Teva: Consultancy; spectrum: Consultancy, Honoraria; Medscape: Consultancy; celgene: Consultancy; Research to Practice: Consultancy; Amgen: Consultancy; Abbvie: Consultancy. Kapoor:Takeda: Research Funding; Celgene: Research Funding. Ailawadhi:Amgen: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Pharmacyclics: Research Funding; Celgene: Consultancy. Reeder:Affimed: Research Funding. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Lacy:Celgene: Research Funding. Kumar:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ansell:Seattle Genetics: Research Funding; Celldex: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Merck & Co: Research Funding; Affimed: Research Funding; Regeneron: Research Funding.
Lenalidomide in Combination with Standard R-CHOP Overcomes the Negative Prognostic Value of Peripheral Blood Absolute Lymphocyte/Monocyte Ratio at Diagnosis and during Treatment in Patients with Diffuse Large B-Cell Lymphoma

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 4139-4139

10.1182/blood-2018-99-114010

Abstract Introduction. The peripheral blood absolute lymphocyte (ALC)/monocyte (AMC) ratio (ALC/AMC), as a surrogate of host immunity (i.e. ALC) and tumor microenvironment (i.e. AMC), is a predictive biomarker for clinical outcomes in diffuse large B-cell (DLBCL) patients. An ALC/AMC ratio ≥ 1.1 has been shown to be predictive of better survival both at baseline and during each therapy cycle in patients treated with R-CHOP [Porrata et al, 2014]. Lenalidomide is an immunomodulatory drug, effective in DLBCL patients, with various mechanisms of actions on the tumor microenvironment and the host immune response. In this study we analyze the prognostic value of ALC/AMC ratio in a cohort of newly diagnosed DLBCL patients treated with Lenalidomide plus R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone, R2-CHOP) in a phase II trial (MC078E trial, [Nowakowski et al, 2015]). Methods. All patients with de-novo DLBCL enrolled in the phase II trial MC078E and treated at diagnosis with R2-CHOP regimen were included in the analysis. We investigated the ALC/AMC ratio at baseline and each R2-CHOP cycle as predictor of progression-free survival (PFS) and overall survival (OS). The ALC/AMC ratio was obtained by dividing the ALC by the AMC from the automated white blood cell differential obtained from the complete blood cell count on day 0 of each treatment cycle (range from day -3 to day 0 of each course). Patients were then divided in 4 groups on the basis of pattern of ALC/AMC ratio during treatment: group A: patients with ALC/AMC ratio ≥ 1.1 throughout all cycles; group B: patients with ALC/AMC ratio ≥ 1.1 at baseline, but then obtained an ALC/AMC < 1.1 during treatment; group C: patients with ALC/AMC ratio < 1.1 at baseline, but then gained an ALC/AMC ≥ 1.1 during treatment; group D: patients with ALC/AMC ratio < 1.1 throughout all cycles. PFS and OS were analyzed in the different groups. We separately conducted the same analysis in a matched control cohort of 94 DLBCL patients from the Mayo Clinic Lymphoma Database treated with standard R-CHOP. Results. A total of 63 patients with de-novo DLBCL treated with R2CHOP regimen at diagnosis were included in the analysis. Clinical characteristics were: median age 67 years (22-87), male sex 61.9%, III-IV advance stage 87.3%, elevated LDH serum levels 66.7%, intermediate-high/high International Prognostic index (IPI) score in 54% cases. No differences in 3y-PFS and 3y-OS in patients with ALC/AMC ratio ≥ 1.1 vs ALC/AMC < 1.1 at baseline and at each R2-CHOP course have been observed. In a landmark analysis from day 0 of the last cycle, 3y-PFS in group A vs B vs C vs D was: 71.4% vs 67.1% vs 66.7% vs 85.7%, respectively (p 0.80); 3y-OS in group A vs B vs C vs D was: 85.7% vs 86.5% vs 66.7% vs 100%, respectively (p 0.74). No differences in both 3y-PFS and 3y-OS were observed comparing group A vs B, in group C vs D, and in group A vs D. Unlike what was observed in the R-CHOP treated DLBCL patients, in a univariate analysis ALC/AMC < 1.1 during all cycles of R2CHOP was not a predictor for inferior outcomes (Figure 1.a). In the matched cohort of patients treated with standard R-CHOP, ALC/AMC < 1.1 at baseline and at each course demonstrated to be predictive of worse outcome (p <0.01),survival was significantly different in the 4 groups identified according to ALC/AMC ratio during treatment and ALC/AMC < 1.1 maintained during all cycles of R2CHOP was predictive of worse PFS and OS (Figure 1.b). Conclusions. Lenalidomide in combination with standard R-CHOP (R2-CHOP), in previously untreated DLBCL patients, appears to overcome the negative prognostic value of ALC/AMC ratio observed in patients treated with R-CHOP alone. This could reflect the additional effect of lenalidomide to standard therapy on tumor microenvironment and on host immunity response. Figure 1: Landmark Analysis for Progression Free Survival and Overall Survival by ALC/AMC groups within R2CHOP (1.A) and R-CHOP (1.B). Group A: ALC/AMC >=1.1 for all cycles; Group B: ALC/AMC >=1.1 at baseline and obtained <1.1 during treatment; Group C: ALC/AMC <1.1 at baseline and obtained >=1.1 during treatment; Group D: ALC/AMC <1.1 for all cycles. Disclosures Witzig: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.
Updated Efficacy and Safety, and Exploratory Ki-67 Results For The MCL-001 Study Of Lenalidomide In Mantle Cell Lymphoma Patients Who Relapsed Or Were Refractory To Bortezomib

Blood | October 14, 2019 | Volume: 122 | Issue: 21 | Pages: 3057-3057

10.1182/blood.v122.21.3057.3057

Abstract Introduction Patients with mantle cell lymphoma (MCL) typically respond to initial therapy and almost inevitably relapse with frequent chemoresistance over time and poor outcome. Multiple phase II studies have established the efficacy and safety of lenalidomide, an immunomodulatory agent with tumoricidal and antiproliferative properties, in relapsed/refractory MCL. The prospective phase II multicenter MCL-001 “EMERGE” study led to FDA approval of lenalidomide for patients with relapsed/refractory MCL after 2 prior treatments, that included bortezomib. The activity of lenalidomide was seen regardless of MIPI, number of prior therapies, prior high dose therapy, bulky disease or high tumor burden. One of the most established prognostic factors in MCL is the proliferation index Ki67 (MIB1), now confirmed both in standard and dose-intensive high-dose therapy strategies. We present here longer follow-up of efficacy and safety from the MCL-001 study in patients relapsed/refractory to bortezomib and the potential relationship between Ki-67 and efficacy outcomes. Methods Patients with heavily pretreated MCL, that included prior bortezomib, received lenalidomide 25 mg/day PO, days 1-21 in 28-day cycles until disease progression or intolerability. Primary study endpoints were overall response rate (ORR) and duration of response (DOR); secondary endpoints included complete response (CR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and safety. Response rates and time-to-event data were analyzed by independent central reviewers per modified IWG criteria and Kaplan-Meier estimates respectively (data cut-off March 20, 2013). Ki-67 was examined as an exploratory endpoint by immunohistochemistry for 81/134 patients (60%) either performed on biopsy samples for 24 patients, or based on the Ki-67 scores reported in local pathology reports for 57 patients. Results Median age for the enrolled intent-to-treat patient population (N=134) was 67 years (range, 43-83; 63% ≥65 years). The median number of previous therapies was 4 (range, 2-10; 78% received ≥3), 93% stage III/IV, and 72% were <6 months from last prior treatment. At a median follow-up of 13.2 months, the ORR was 28% (CR/CRu 8%), with a median DOR of 16.6 months (95% CI, 9.2-26.7; median not reached in patients with CR/CRu) by central review. Median TTR was 2.3 months (95% CI, 1.7-13.1), with a median time to CR/CRu of 4.1 months (95% CI, 1.9-13.2). Median PFS was 4.0 months (95% CI, 3.6-6.9), and median OS was 20.9 months (95% CI, 13.7-24.4). The average dose intensity of lenalidomide was 20 mg/day, for a median duration of 94.5 days (range, 1-1,256). Dose reductions or interruptions due to adverse events (AEs) occurred in 40% and 58% of patients, respectively. Neutropenia (44%), thrombocytopenia (28%), and anemia (11%) were the most common treatment-related grade 3/4 AEs. Ki-67 results were available in 81/134 patients, and efficacy data were categorized using 30% and 50% cut-off thresholds for Ki-67 expression (Table 1). Although patient numbers were limited, the ORR was similar in both lower and higher Ki-67 group, but those with lower Ki-67 levels demonstrated better CR rates, DOR and survival outcomes compared with patients with elevated Ki-67. Conclusions Single-agent lenalidomide in heavily pretreated patients with relapsed/refractory MCL post-bortezomib showed durable long-term efficacy with a consistent safety profile. Consistent with what is reported in the literature, high Ki-67 is associated with poor outcome in our cohort with shorter OS. Though based on retrospective evaluation and subsets of patients, the ORR to lenalidomide was similar in both low and high Ki-67 groups, suggesting lenalidomide can be active in patients expressing high levels of Ki67. Prospective studies are needed to confirm these findings. Disclosures: Goy: Celgene: Consultancy, Research Funding, Speakers Bureau. Off Label Use: This is a phase 2 clinical study of safety and efficacy for lenalidomide in patients with MCL. Williams:Celgene: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Drach:Celgene: Honoraria. Ramchandren:Celgene: Research Funding. Zhang:Celgene: Employment. Cicero:Celgene: Employment. Fu:Celgene: Employment. Heise:Celgene: Employment, Equity Ownership. Witzig:Celgene: Research Funding.
Relapses after Achieving EFS24 in Patients with Diffuse Large B-Cell Lymphoma in the Rituximab Era

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 454-454

10.1182/blood-2018-99-113213

Abstract Introduction: The addition of Rituximab to chemotherapy has significantly improved the outcome of patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). Patients treated with immunochemotherapy for DLBCL who achieve EFS24 (event-free for 2 years after diagnosis) have an overall survival equivalent to that of the age- and sex-matched general population. Relapses after achieving EFS24 have been considered to be unusual but have been understudied. We sought to define the rate, clinical characteristics, treatment pattern, and outcomes of such relapses. Methods: 1448 patients with newly diagnosed DLBCL from March 2002 to June 2015 were included. Patients were enrolled in the Molecular Epidemiology Resource (MER) of the University of Iowa/Mayo Clinic Lymphoma SPORE, treated per physician choice (predominantly R-CHOP immunochemotherapy) and followed prospectively. An event was defined as progression or relapse, unplanned re-treatment after initial therapy, or death from any cause. Cumulative incidence of relapse and non-relapse mortality after achieving EFS24 were analyzed as competing events using Gray's test in the EZR software. Post-relapse survival was defined as time from relapse to death from any cause and analyzed using Kaplan-Meier method in SPSS (V22). Results: Among the 1448 patients, 1260 (87%) had DLBCL alone at diagnosis, and 188 (13%) had concurrent indolent lymphoma (follicular lymphoma 115, marginal zone lymphoma 18, chronic lymphocytic leukemia 14, lymphoplasmacytic lymphoma 4, unspecified 37) at diagnosis. After a median follow-up of 83.9 months, 896 patients achieved EFS24. For all 896 patients who achieved EFS24, the cumulative incidence of relapse (CIR) was 5.7%, 9.3% and 13.2%, respectively, at 2, 5 and 10 years after achieving EFS24. Patients with concurrent indolent lymphoma at diagnosis had a higher CIR compared to those with DLBCL alone at diagnosis (10.2 vs 4.8% at 2 years, 15.7 vs 8.0% at 5 years, 28.8 vs 9.7% at 10 years, P<0.001; Figure 1). There were a total of 84 patients who relapsed after achieving EFS24. The median age at initial diagnosis was 66 years (range 35-92), and 48 (57%) were male. At diagnosis, 11 (13%) had ECOG PS >1, 37 (50%) had LDH elevation, 62 (74%) were stage III-IV, 14 (17%) had more than 1 extranodal site, and 26 (31%) were poor risk by R-IPI score. There were 58 patients with DLBCL alone at diagnosis who relapsed after achieving EFS24, and 38 (75%) relapsed with DLBCL, 13 (25%) relapsed with indolent lymphoma (predominantly follicular lymphoma), and pathology was unknown in 7 patients. In contrast, there were 26 patients with concurrent indolent lymphoma at diagnosis who relapsed after achieving EFS24, and 9 (41%) relapsed with DLBCL, 13 (59%) relapsed with indolent lymphoma, and pathology was unknown in 4 patients. In the 47 patients who relapsed with DLBCL after achieving EFS24, 45% received intensive salvage chemotherapy, 19% received regular intensity chemotherapy, 9% received CNS directed chemotherapy, and 36% went on to receive autologous stem cell transplant (ASCT). In the 26 patients who relapsed with indolent lymphoma after achieving EFS24, 27% were initially observed, 54% received regular intensity chemotherapy, 4% received intensive salvage chemotherapy, and 19% received ASCT after subsequent progression. The median post-relapse survival (PRS) for all patients with a relapse after achieving EFS24 was 38.0 months (95% CI 27.5-48.5). The median PRS for patients who relapsed with DLBCL and indolent lymphoma after achieving EFS24 were 29.9 (19.9-39.9) and 89.9 (NR-NR) months, respectively (P=0.002; Figure 2). Conclusions: Relapses after achieving EFS24 in patients with DLBCL were uncommon in the rituximab era. Patient with DLBCL alone at diagnosis can relapse with either DLBCL or indolent lymphoma (3:1 ratio). Patients with concurrent DLBCL and indolent lymphoma at diagnosis had a significantly higher CIR, and relapses with DLBCL and indolent lymphoma were similar (2:3 ratio). Even with high intensity salvage chemotherapy and consolidative ASCT, patients who relapsed with DLBCL had a significantly worse survival compared to those who relapsed with indolent lymphoma. Late relapses with DLBCL remain clinically challenging, with a median survival of 2.5 years after relapse. Figure 1. Figure 1. Disclosures Maurer: Celgene: Research Funding; Nanostring: Research Funding; Morphosys: Research Funding. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ansell:Takeda: Research Funding; Pfizer: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Celldex: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Merck & Co: Research Funding; Bristol-Myers Squibb: Research Funding. Cerhan:Celgene: Research Funding; Jannsen: Other: Scientific Advisory Board; Nanostring: Research Funding.
Short Time between Progression after Immunochemotherapy and Initiation of Salvage Therapy (PTI) Is Associated with Inferior Long-Term Outcomes in Patients with Relapsed/Refractory DLBCL

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 4204-4204

10.1182/blood-2018-99-114331

Abstract Background An association has been identified between the diagnosis-to-treatment interval (DTI) and prognostic clinical factors and outcomes in patients with previously untreated diffuse large B-cell lymphoma (DLBCL) (Maurer et al, JCO 2018). This association can result in inadvertent selection bias in clinical trials to exclude patients with aggressive disease due to the inability to delay treatment long enough to fulfill enrollment criteria, compromising the validity of clinical trial study results to the general population. A similar concern exists in the relapsed/refractory (r/r) DLBCL setting regarding patient selection bias against patients with aggressive disease requiring immediate treatment following relapse or progression. Here we examine the time from progression after immunochemotherapy (IC) to the initiation of first salvage chemotherapy and its association with outcome. Patients and Methods: Newly diagnosed patients were prospectively enrolled within 9 months of diagnosis in the University of Iowa/Mayo Clinic Lymphoma SPORE Molecular Epidemiology Resource (MER), now a subcohort of the Lymphoma Epidemiology of Outcomes (LEO) Cohort Study, and followed for progression/relapse, retreatment, and death. This analysis includes patients with their first r/r DLBCL following frontline IC who initiated aggressive salvage chemotherapy as identified and included in a previous publication (Farooq et al, BJH 2017). The progression-to-treatment interval (PTI) was defined as the time in days from date of progression from IC to initiation of salvage therapy. The date of progression was defined as either a) the date biopsy was obtained for patients who had a biopsy to confirm progressive disease or b) the date of the scan or clinical examination indicating progression in patients who did not have a biopsy performed. Event-free survival (EFS) was defined as time from initiation of first salvage therapy to progression or relapse, initiation of new anti-lymphoma therapy, or death due to any cause; overall survival (OS) was defined as time from initiation of salvage therapy until death due to any cause. Results: 162 patients with r/r DLBCL enrolled in the MER from 2002-2012 who initiated aggressive salvage chemotherapy with intent to transplant and had confirmed dates for both progression after IC and start of salvage therapy were evaluated. Median age at first progression for these patients was 64 years (range 36-76) and 104 (64%) were male. Median time from diagnosis to first progression on IC was 6.7 months (IQR: 4.6-12.7). Initial salvage therapy was R-ICE (80%), R-DHAP (8%), rituximab, oxaliplatin, cytosine arabinoside, and dexamethasone (ROAD) (6%), and other (7%). At a median follow-up of 49 months from initiation of salvage therapy (IQR: 33-74), 116 patients had died (72%). Median PTI was 6 days (IQR: 2-13). 110 patients (68%) had biopsy confirmation of disease prior to initiating salvage therapy; median PTI was 2 days (IQR: 1-7) for patients who had biopsy confirmation vs. 7 days (IQR: 3-16) in patients without biopsy confirmation, Wilcoxon p=<0.0001. There was no difference in OS from initial salvage therapy between patients who did not have biopsy confirmation (HR=1.09, 95% CI: 0.74-1.60, p=0.68) compared to patients with biopsy confirmation. Patients with short PTI (0-6 days) had significantly worse overall survival from initiation of salvage therapy (median OS = 7.6 months, HR=2.10 (95% CI: 1.43-3.08) compared to patients who initiated therapy 7 or more days from progression (median OS = 29.7 months), logrank p<0.0001. This association remained consistent (HR=2.20, 95% CI: 1.48-3.26, p<0.0001) after adjusting for age and biopsy confirmation of progression. Short PTI was also associated with inferior response rate to initial salvage therapy (51% vs. 65%, p=0.058), lower rate of proceeding to transplant after initial salvage therapy (33% vs. 55%, p=0.0063), lower rate of being event-free 24 months from initial salvage therapy (16% vs 33%, p=0.011) and lower rate of ever proceeding to transplant (44% vs. 59%, p=0.057). Conclusions: A short progression-to-treatment interval is strongly associated with inability to proceed to transplant and inferior overall survival in r/r DLBCL. These results have implications for the design and interpretation of clinical trials in the relapsed/refractory setting. Figure. Figure. Disclosures Maurer: Celgene: Research Funding; Nanostring: Research Funding; Morphosys: Research Funding. Ansell:Trillium: Research Funding; Merck & Co: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Pfizer: Research Funding; Celldex: Research Funding; Takeda: Research Funding. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Cerhan:Nanostring: Research Funding; Celgene: Research Funding; Jannsen: Other: Scientific Advisory Board.
Ibrutinib Therapy in Patients with Waldenstrom Macroglobulinemia: Outcomes Outside of Clinical Trial Setting

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 1606-1606

10.1182/blood-2018-99-120044

Abstract Background : Ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor was approved for the treatment of Waldenstrom Macroglobulinemia (WM) in January, 2015 based on the results of a clinical trial of 63 previously-treated patients with WM. Data on outcomes with ibrutinib outside of clinical trials are limited. Methods : Medical records of patients with WM seen consecutively between 02/01/2015 and 06/01/2018 at Mayo Clinic, MN, FL and AZ were reviewed and those treated with ibrutinib at any point during their disease were included. Refractoriness to prior therapy was defined as disease progression on therapy or within 2 months of stopping treatment. The response rates were assessed by WM VI International Workshop Criteria. Adverse events were graded using National Cancer Institute Common Toxicity Criteria for Adverse Events (AEs) v4.03. All time-to-event analyses were performed from the time of initiation of ibrutinib. Results : Eighty patients [previously treated, n=67 (84%), treatment-naïve, n=13 (16%)] received ibrutinib for active WM. Median follow-up was 18 months (95% CI: 12-19) and the median overall survival (OS) was not reached (NR) (95% CI: 27-NR) for the entire cohort at the date of last follow-up. The median age was 67 years (range: 50-88) and the median ECOG performance score was 1 (range: 0-3) at the time of ibrutinib initiation. Median lines of therapies prior to ibrutinib for the previously-treated patients was 2 (range: 1-9) and 35 patients (44%) had received ≥3 prior lines of therapy. Of the 80 patients, 52 patients (43 previously treated, 9 treatment-naïve) had data for response assessment. The baseline characteristics and laboratory parameters at initiation of ibrutinib are outlined in Table 1a and prior therapies are mentioned in Table 1b. Overall response rate (ORR) was 90% (100% in patients with ibrutinib as primary therapy and 88% in salvage therapy setting); major-response rate (MRR) was 77%. Median time to first and best response was 2.1 months (95% CI: 1.5-3.5) and 5.4 months (95% CI: 3.5-13), respectively. Other clinically relevant endpoints and AEs related to ibrutinib therapy are outlined in Table 2 and 3, respectively. The median time-to-next therapy was 33 months (95% CI: 28-NR). At last follow-up, 25 (32%) patients had discontinued ibrutinib therapy. The reasons for discontinuation was progression (n=8), elevated liver enzymes (n=4), cognitive changes (n=1), inability to achieve better than MR (n=1), atrial fibrillation (n=3), consolidation with autologous stem cell transplantation after PR with ibrutinib (n=1), transition to hospice care due to progressive head and neck cancer (n=1), infection in lower extremity (n=1), transformation to DLBCL (n=1), blistering rash which resolved after ibrutinib discontinuation (n=1), obscure GI bleed that resolved after ibrutinib discontinuation (n=1), fatigue (n=1) and for unclear reasons recorded as treatment intolerance (n=1). Following discontinuation of ibrutinib, 21 patients received salvage therapy. Of these, data regarding the response to salvage therapy was available in 9 (43%) patients (VGPR=2, PR=3, SD=3 and progressive disease=1); median PFS from the salvage therapy following ibrutinib discontinuation was 18 months (95% CI: 2-25). Of the 4 patients who were not treated following ibrutinib discontinuation; 1 elected hospice care due to concurrent head and neck cancer progression, and the other 3 patients elected to be monitored off therapy (one had achieved SD and two had PR from ibrutinib). Fourteen patients were evaluable for IgM rebound following ibrutinib discontinuation. Of those, 5 (36%) had sudden increase in IgM level [median: 158% from the IgM level after ibrutinib discontinuation (range: 22%-1368%)] within a median of 2 months (range: 1-3 months) and 1 patient required plasmapheresis for symptomatic hyperviscosity. Four of 5 patients received salvage therapy between 0-15 months. At last follow-up, 11 patients (14%) had died of whom 3 were on ibrutinib at the time of death [CNS involvement, (n=1), causes unrelated to WM, (n=2)]. Conclusions : Ibrutinib is an effective agent in WM patients with MYD88L265Pmutation. Our data regarding outcomes in non-trial setting appear comparable to the results observed in the pivotal clinical trial. Hematologists should be aware of unique ibrutinib associated toxicities and clinically relevant IgM rebound phenomenon following abrupt discontinuation of ibrutinib. Disclosures Ailawadhi: Celgene: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Pharmacyclics: Research Funding; Amgen: Consultancy. Gertz:janssen: Consultancy; Prothena: Honoraria; Medscape: Consultancy; Teva: Consultancy; celgene: Consultancy; annexon: Consultancy; Alnylam: Honoraria; Physicians Education Resource: Consultancy; spectrum: Consultancy, Honoraria; Apellis: Consultancy; Amgen: Consultancy; Abbvie: Consultancy; Ionis: Honoraria; Research to Practice: Consultancy. Kumar:Novartis: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Lacy:Celgene: Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dingli:Millennium Takeda: Research Funding; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Millennium Takeda: Research Funding. Kapoor:Celgene: Research Funding; Takeda: Research Funding.
Phase I Trial of Systemic Administration of Vesicular Stomatitis Virus Genetically Engineered to Express NIS and Human Interferon, in Patients with Relapsed or Refractory Multiple Myeloma (MM), Acute Myeloid Leukemia (AML), and T-Cell Neoplasms (TCL)

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 3268-3268

10.1182/blood-2018-99-119444

Abstract Background: We previously reported successful treatment of myeloma with an oncolytic virus, MMV-NIS. Preexisting immunity against measles made use of that virus unsatisfactory. The Indiana strain of Vesicular Stomatitis Viruses (VSV) are being developed as anticancer drugs for the treatment of a variety of malignancies. To ensure tumor selective replication and spread, we designed the VSV to encode interferon beta. Expression of IFNβ also serves as a STING agonist to activate host immunity against the cancer. The sodium iodide symporter (NIS) is inserted as a reporter gene into the viral genome to enable noninvasive monitoring of viral spread using PET/CT imaging. We report a Phase I clinical trial of intravenous administration of VSV-IFNβ-NIS for relapsed hematological malignancies including MM, AML, and TCL. Methods: Arm A consisted of patients with low tumor burden. Arm B included patients with high tumor burden. Both arms consisted of a classical 3+3 phase I trial, starting at 5x10^9 TCID50 (dose level 1) through 5x10^11 TCID50 (dose level 4), given as a single IV dose. In order to obviate potential toxicity from high interferon levels, Arm B received ruxolitinib 15 mg twice daily for 10 days beginning on day -1. The primary objective was determining the maximum tolerated dose (MTD) of VSV-IFNβ-NIS alone and in combination with ruxolitinib; secondary objectives include estimating the safety profile and preliminary efficacy. Correlative objectives include monitoring the pharmacodynamics of viral replication through SPECT/CT imaging with NIS gene, viremia, virus shedding, changes in the immune profile of peripheral blood leukocytes, and immunohistochemistry for immune cell infiltrates in tumors. Adverse events (AEs) are reported herein based on CTCAE v4 with the exception of cytokine release syndrome (CRS) which is based on Lee (Blood 2014; 124(2):188-195) criteria. Results: To date, 10 patients have received IV VSV-IFNβ-NIS; 8 in Arm A and 2 in Arm B. In Arm A, 3 patients were treated at dose level 1, 3 at dose level 2 and 2 at dose level 3. At dose level 1, there were three grade 3 hematologic AEs (neutropenia [1], lymphopenia [2]), and no grade 3+ non-hematologic AEs. At dose level 2, there were two grade 3 hematologic AEs (anemia [1], lymphopenia [1]), and two grade 3 non-hematologic AEs (nausea [1], dehydration [1]). A grade 2 CRS by Lee criteria was also observed. At dose level 3, 2 patients have been enrolled and data are maturing for DLT evaluation. In Arm B (VSV + rux), 2 patients have been enrolled and data are maturing for dose limiting toxicity (DLT) evaluation. Other grade 1 and 2 toxicities have included fever, hypertension, headache, electrolyte abnormalities, nausea, vomiting, transient elevation of liver function tests and creatinine. All grade 1 and 2 toxicities resolved within 72 hours. Among the 6 patients evaluable for response, there was one partial remission (TCL patient treated at dose level 2), and 5 with progressive disease. Multiple cytokines increased at 4h post infusion of virus, but most returned to baseline levels by 24h.Viremia was detectable in all patients at the end of infusion, and to varying levels at 30 mins, 1, 2, 4, 24, 48h or 72 hours post virus infusion. No persistent viremia was observed. No infectious virus was recovered in buccal swabs or urine and neutralizing anti-VSV antibodies were present by day 29. Extensive immune phenotyping and ELIspot assays for shared antigens are ongoing. Conclusion: In the lowest dose levels tested to date, VSV-IFNβ-NIS has not led to any observed dose limiting toxicity. Dose escalation is ongoing and updated results will be reported. Disclosures Lacy: Celgene: Research Funding. Peng:Vyriad: Equity Ownership. Russell:Vyriad: Equity Ownership. Dueck:Bayer: Employment; Phytogine: Employment; Pfizer: Honoraria. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Gertz:spectrum: Consultancy, Honoraria; Physicians Education Resource: Consultancy; Ionis: Honoraria; janssen: Consultancy; Medscape: Consultancy; celgene: Consultancy; Apellis: Consultancy; Prothena: Honoraria; Amgen: Consultancy; annexon: Consultancy; Abbvie: Consultancy; Research to Practice: Consultancy; Teva: Consultancy; Alnylam: Honoraria. Dingli:Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Millennium Takeda: Research Funding; Alexion Pharmaceuticals, Inc.: Other: Participates in the International PNH Registry (for Mayo Clinic, Rochester) for Alexion Pharmaceuticals, Inc.; Millennium Takeda: Research Funding. Kapoor:Celgene: Research Funding; Takeda: Research Funding. Al-Kali:Novartis: Research Funding. Naik:Vyriad: Equity Ownership. Kumar:AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding.
Avadomide (CC-122), a Novel Cereblon Modulating Agent, Plus Rituximab in Patients with Relapsed or Refractory Follicular Lymphoma

Blood | October 14, 2019 | Volume: 132 | Issue: Supplement 1 | Pages: 1602-1602

10.1182/blood-2018-99-114409

Abstract Introduction:The prognosis is poor for patients with follicular lymphoma (FL) who experience early relapse within 2 years of initial diagnosis and for those who are double refractory to both rituximab and chemotherapy (Casulo et al. J Clin Oncol 2015). Avadomide, a cereblon-modulating agent that promotes degradation of the hematopoietic transcription factors Aiolos and Ikaros, is being examined in this setting. Avadomide demonstrated promising clinical activity in combination with obinutuzumab or rituximab in relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and FL (Michot et al. Blood 2017; Ribrag et al. Blood 2017). Herein, we report FL subgroup analyses for the avadomide plus rituximab combination (Arm D) of the CC-122 DLBCL-001 study in both lenalidomide-naïve and treated patients. Methods: CC-122-DLBCL-001 (NCT02031419) is aphase Ib dose escalation/expansion study of avadomide, CC-223, and CC-292 given orally as doublets, and as triplets in combination with rituximab, as well as avadomide plus rituximab doublets, in patients with R/R DLBCL or FL after ≥1 prior line of therapy. In the dose expansion phase of the study, patients received avadomide once daily (QD) for 5 days/week (5/7 d), with a fixed dose of intravenous rituximab 375 mg/m2/cycle (28-day cycle). The study endpoints were safety, tolerability, pharmacokinetics, preliminary efficacy (overall response rate [ORR] and complete response [CR]), and blood pharmacodynamic markers of avadomide. Results: As of May 1, 2018, 37 patients with FL were enrolled in the Arm D expansion group, including 29 in cohort 1 (no prior lenalidomide) and 8 in cohort 2 (≥2 cycles of prior lenalidomide). Baseline patient characteristics were similar between the two cohorts. In the total FL population, the median age was 61 years (range, 41-81 years), 54% were male, and 46% had an Eastern Cooperative Oncology Group performance status of 1. The median number of prior systemic anticancer regimens was 3 (range, 1-8). At disease diagnosis, three patients (8%) had bulky disease (≥7 cm in single dimension) and 7 (19%) had high Follicular Lymphoma International Prognostic Index scores. Twenty-three patients (62%) were refractory to rituximab and 11 (30%) were double-refractory to rituximab and an alkylating agent. As of the data cutoff, 27 patients (71%) were ongoing and no evaluable patients had experienced a dose-limiting toxicity. The most common (≥10%) any-grade adverse events (AEs) were neutropenia (46%) and anemia (24%). Grade 3/4 AEs occurring in >1 patient were neutropenia (32%); fatigue, dizziness, and anemia (8% each); febrile neutropenia and diarrhea (5% each). Six patients (16%) experienced serious AEs related to study drugs. One patient died during the study (sepsis considered possibly related to study treatment). Avadomide dose reduction occurred in 7 (19%) patients. Among all FL patients, the ORR was 65% with 8 patients (22%) achieving a CR. Response rates appeared to be independent of prior lenalidomide treatment, with an ORR of 62% (CR=14%) in cohort 1 and an ORR of 75% (CR=50%) in cohort 2. The median follow up for progression-free survival (PFS) was 6.3 months and 49% of patients had <6 months of PFS follow up. In the total FL population, 6-month and 12-month PFS rates were 83 (95% CI, 64-93) and 66 (37-84), respectively. Conclusions: Avadomide combined with rituximab was well tolerated. AEs were generally consistent with the known safety profile of avadomide and toxicities associated with rituximab. Moreover, this combination showed promising efficacy in patients with R/R FL independent of prior treatment with lenalidomide. These findings support the role of avadomide plus an anti-CD20 antibody as a novel chemotherapy-free treatment for this difficult to treat patient population. Disclosures Nastoupil: TG Therappeutics: Research Funding; Karus: Research Funding; Novartis: Honoraria; Merck: Honoraria, Research Funding; Juno: Honoraria; Celgene: Honoraria, Research Funding; Gilead: Honoraria; Janssen: Research Funding; Spectrum: Honoraria; Genentech: Honoraria, Research Funding. Ribrag:Amgen: Research Funding; Roche: Honoraria, Other: travel; epizyme: Consultancy, Honoraria; MSD: Honoraria; Infinity: Consultancy, Honoraria; NanoString Technologies: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Other: travel; Servier: Consultancy, Honoraria; pharmamar: Other: travel; Gilead: Consultancy, Honoraria; Incyte Corporation: Consultancy; argenX: Research Funding. Chavez:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Humanigen: Consultancy; Merck: Research Funding; Kite: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Speakers Bureau. Witzig:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Andorsky:AstraZeneca: Consultancy; Genentech: Consultancy; Celgene: Research Funding; CTI BioPharma: Consultancy, Research Funding. Corradini:Janssen: Honoraria, Other: Lecturer; Amgen: Honoraria, Other: Advisory Board & Lecturer; Gilead: Honoraria, Other: Advisory Board & Lecturer; Celgene: Honoraria, Other: Advisory Board & Lecturer; Roche: Honoraria, Other: Advisory Board & Lecturer; Takeda: Honoraria, Other: Advisory Board & Lecturer; Sanofi: Honoraria, Other: Advisory Board & Lecturer; Novartis: Honoraria, Other: Advisory Board & Lecturer; Abbvie: Honoraria, Other: Advisory Board & Lecturer; Sandoz: Other: Advisory Board. Flinn:ArQule: Research Funding; Agios: Research Funding; TG Therapeutics: Research Funding; Calithera: Research Funding; BeiGene: Research Funding; Verastem: Consultancy, Research Funding; Janssen: Research Funding; Curis: Research Funding; Pharmacyclics: Research Funding; Incyte: Research Funding; Trillium: Research Funding; Forty Seven: Research Funding; Kite: Research Funding; Pfizer: Research Funding; Verastem: Research Funding; Novartis: Research Funding; Genentech: Research Funding; Merck: Research Funding; Portola: Research Funding; Takeda: Research Funding; Seattle Genetics: Research Funding; Constellation: Research Funding; Forma: Research Funding; Celgene: Research Funding; Gilead: Research Funding; Infinity: Research Funding. Sangha:Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria, Membership on an entity's Board of Directors or advisory committees; Lundbeck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche/Genentech: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; BI: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees. Uttamsingh:Celgene Corporation: Employment, Equity Ownership. Hagner:Celgene Corporation: Employment, Equity Ownership. Gandhi:Celgene Corporation: Employment, Equity Ownership. Chen:Celgene Corporation: Employment, Equity Ownership. Hege:Mersana: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; SITC: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Employment, Equity Ownership, Patents & Royalties: multiple; Arcus Biosicences: Membership on an entity's Board of Directors or advisory committees. Pourdehnad:Celgene Corporation: Employment, Equity Ownership. Kuruvilla:Celgene: Honoraria; Roche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria; Lundbeck: Honoraria; BMS: Consultancy, Honoraria; Abbvie: Consultancy; Merck: Consultancy, Honoraria; Amgen: Honoraria; Seattle Genetics: Consultancy, Honoraria; Karyopharm: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Princess Margaret Cancer Foundation: Research Funding; Leukemia and Lymphoma Society Canada: Research Funding.